Lay-in type suspended ceiling and panel therefor



May 5, 1970 D. w. AKERSON 3,509,671

LAY-IN TYPE SUSPENDED CEILING AND PANEL THEREFOR Filed Dec. 4, 1967 INVENTOR. DV/D W A/(ERSON Arm/ME United States Patent 3,509,671 LAY-IN TYPE SUSPENDED CEILING AND PANEL THEREFOR David W. Akerson, St. Paul, Minn., assignor to Conwed Corporation, St. Paul, Minn., a corporation of Delaware Filed Dec. 4, 1967, Ser. No. 687,583 Int. Cl. E04b 1/86, /52

US. or. 51-145 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a lay-in ceiling as distinguished from a tile ceiling.

One object of this invention is to provide the lay-in panels with a metal foil facing similar to those heretofore used only on tiles.

Another object of this invention is to provide a washable, and repeatedly washable, facing on lay-in panels, which facing also provides a damage resistant surface.

These and other objects will be understood by those skilled in the art from the accompanying specification and drawings in which:

FIG. 1 is a prospective view from beneath of a lay-in ceiling, and

FIG. 2 is an enlarged view of one edge of one of the panels from FIG. 1.

Of the many types of ceilings currently being installed, particularly in commercial construction, two of the most common are referred to in the industry as lay-in systems and tile systems. As understood in the industry, and as used herein, the two systems may be distinguished largely by difference in size.

Commonly, lay-in ceilings incorporate panels or boards of a dimension of at least 2' x 2. In contrast, tile ceilings utilize tiles of generally 1' x 1, although sometimes such tiles are provided in 1' x 2' sizes.

Another distinguishing feature between the lay-in systems and tile ceilings is that the large panels of the lay-in ceilings are supported by resting upon a grid made up of runners and cross-members which are of an inverted T shape in cross section. Thus the lay-in panels merely rest on the suspension system, which is generally referred to as an exposed system. In contrast, tiles are mounted in a number of ways which do not normally expose the suspension system. Tiles may be nailed, screwed, or adhered to a completed ceiling, or they may be mounted in a suspension system specifically designed to hide the suspension system in kerfs cut into edges of the tiles.

Lay-in panels are merely square cut on their edges and extend in size, as indicated above, from 2' x 2' in dimension on up, with 2' x 4 being the most common dimension. Larger sizes are sometimes provided, but normally not in excess of 2 in width. Thus, panels 2' x 5' and 2' x 6' are known.

The lay-in system generally enjoys a greater volume of sales in the industry, due largely to the lesser cost per square foot of producing a square cut board as opposed to one requiring additional working of the edges, such as is required with tiles. Another reason for the general economy of lay-in systems is the ease of installation and the minimum amount of suspension system needed.

For certain applications, however, lay-in panels have not heretofore been acceptable. Generally, in areas of See excessive humidity, such as restaurant kitchens, bathrooms, and swimming pool areas, a highly washable surface is required. For these types of applications, recourse has been had to tile systems in which the tiles are faced with a metal foil, generally extending at least part way up the edges of the tiles. Such metal foils serve to provide a hard and washable surface for such applications as mentioned above where repeated washing or sanitizing, such as in hospitals, is required.

Previously, lay-in panels have not been provided with metal foil facings. It is not known exactly why such products have not been available; however, it is believed due to the fact that large panels tend to sag or pillow in the center, thus giving an undulating and unpleasing appearance to the ceiling.

Because of fire code requirements, most all of the materials referred to are made from mineral fibers bound together with a suitable binder. The common binder is starch, which is hydrophilic. Starch, of course, is used primarily for economy. When such panels are mounted in high humidity areas, being supported only at their edges, the humidity tends to weaken the starch bond, thus permitting the board or panel to sag noticeably toward the center. Any additional weight added to the panel tends to aggravate this difficulty.

Even without added weight, such mineral fiber panels bound with hydrophilic binders have required additional treatment such as a resin coating on the back side in order to bring the sag characteristics within acceptable limits. Under such circumstances it was not to be expected that the added weight of metal foil facings could be tolerated, since metal foils are not in themselves self supporting.

In the drawings, FIG. 1 shows a suspension system for lay-in system, including lay-in panels 10, longitudinal runners 12, and cross members 14.

The cross section of a runner 12 is shown in FIG. 1 as comprising a vertical web 16 and horizontally disposed flanges 18 and 20. The cross section of the cross members 14 is not shown but is substantially identical to the cross section of the runners 12.

The runners 12 are supported from a permanent superstructure, such as a concrete deck (not shown), by means of wires 22 fastened to such a deck at one end and at the other end to the web 16 of the runners 12.

It will be seen that the panels 10 merely rest upon the horizontal flanges 18 and 20 of the suspension system runners 12 and cross members 14. As such, the suspension system comprised of the runners 12 and the cross members 14 is exposed, at least to the extent of showing one face of the flanges 18 and 20. This arrangement permits the panels 10 to be removed by pushing upwardly, thus permitting access to pipes, duct work, electrical conduits, and the like hidden above the suspension system ceiling and beneath the deck above. This ease of access is another of the reasons for the general popularity of this type of ceiling.

The panels 10 of the instant invention are also shown in FIG. 2, wherein they are shown to comprise a body portion 24 and a metal foil facing member 26.

The body portion 24 is comprised of felted synthetic mineral fibers bound together by a suitable economic binder such as the hydrophilic binder starch. The facing 26 is preferably of aluminum foil but may be any of a number of other metal foils, such as tin, brass, stainless steel, and the like. -In the preferred embodiment, the foil 26 is an aluminum foil of 4 mils in thickness, although thicknesses as thin as 2 mils may be used. Larger mil thicknesses may, of course, be used; however, such are avoided for reasons of economics.

The metal foil facing 26 is adhered throughout sub- 3 stantially its entire extent by means of an adhesive to the facing surface of the body 24. It has been found that in the absence of such substantially complete adhesion, the panel will not function adequately when in place due to sagging.

The panel is also provided with relatively minute acoustical openings 28 punched through the metal foil 26 and into the body board 24. These acoustical openings are generally of a size of between and in diameter. There are a myriad of such minute perforations in the front surface of the panel 10. These acoustical openings provide access into the sound absorptive body board 24 for acoustical energy-sound-impinging upon the face of the metal foil 26. The metal foil itself is, of course, not acoustically absorptive and the body board 24, in the absence of the openings 28, would not be particularly sound absorptive either. The openings 28 permit the sound to enter well into the body board 24, where the sound is absorbed in known fashion in the interstices of the fibers. Generally the fibers arrange themselves in layers parallel to the plane of the panel 10 and, consequently, some means of introducing the sound energy into the body of the board is required. However, these openings 28 also permit access into the interior of the board for the humidity of the atmosphere which deleteriously affects the hydrophilic binder.

In one accepted test for sagging, a ceiling of lay-in panels is supported in an enclosed tent, or room, where the humidity and temperature may be controlled. In such a test, the maximum permissible limit along the 4 length of a panel is 0.25" downward sagging. Applicant has found, contrary to expectations, that with a metal foil facing such large panels will sag less than said 0.25 limit and usually only between .08 and .15".

It is not known, nor need it be 'known, exactly why the metal foil facings do not deleteriously affect the sag characteristics but, rather, improve the sag characteristics. One theory suggested is that when suspended in a suspension ceiling with the metal foil facing downwardly the foil is placed in tension throughout its length by being adhered to the lay-in board throughout its surface, and in tension such foils are quite strong.

While reference has been made herein to dimnesions of 2' x 2', 2 x 4', and larger 'for the panels 10, it is to be understood that in the industry these dimensions refer to what is called nominal dimensions and that actually such panels will be a few fractions of an inch smaller than the indicated sizes in order to accommodate the thickness of the web 16 and to permit insertion and removal of the panel 10. For example, the nominal 2 x 4' size, which is most common, is in actuality 111%" x 311%".

By the term foil as used herein, applicant refers to metal foils which are of such a thickness as to be not self supporting in the dimensions referred to above, such as the nominal 2 x 2' size or larger.

I claim:

1. A suspended ceiling of the lay-in type comprising a suspension grid having a plurality of parallel runners and a plurality of cross members extending between runners, said runners and cross members being an inverted T shape in cross section, a plurality of acoustical panels supported horizontally by said grid with the edges of said panels resting on the horizontal flanges of said runners and cross members, each of said panels being comprised of mineral fibers bound together by an hydrophilic binder to form a board, said boards being of such a dimension in the plane of the ceiling as normally to sag downwardly due to their weight and the span between runners and cross members when exposed to himidity, a metal foil facing adhered to one face of said board throughout substantially the full extent of said face, acoustical openings extending through said foil and into said board to provide access to the interior of said board for sound energy impinging upon the exposed face of said foil, said panels being mounted in said suspension grid with their foil facing downwardly toward the interior of the room.

2. The construction of claim 1 in which the side edges of said board are free of foil.

3. The construction of claim 1 in which the dimension of said panel is at least substantially 2' x 2.

4. The construction of claim 3 in which the side edges of said board are free of foil.

5. An acoustical panel comprising a board of mineral fibers bound together by an hydrophilic binder, said board being of at least substantially 2' x 2 in dimension in the major plane thereof, a metal foil facing adhered to one face of said board throughout substantially the full extent of said face, and acoustical openings extending through said foil and into said board to provide access to the interior of said board for sound energy impinging upon the exposed face of said foil.

6. The panel of claim 5 in which the side edges of said board are free of foil.

References Cited UNITED STATES PATENTS 1,959,057 5/1934 Kliefoth 181-30 2,028,272 1/ 1936 Burgess 52-145 3,174,580 3/1965 Schulz et a1. 52-145 X 3,246,063 4/1966 Podgurski 181-33 FOREIGN PATENTS 1,103,319 5/1955 France.

990,491 4/ 1965 Great Britain.

ALFRED C. PERHAM, Primary 'Examiner US. Cl. X.R. 

